Knife for turning irregular forms



(No Model.)

, T. W. GARDINER.

KNIFE FOR TURNING IRREGULAR FORMS.

No. 454,041. Patented June 16, 1891.

WOW 533m 3313 SHOT/M a S UNITED STATES PATENT OFFICE.

THOMAS W. GARDINER, OF \VOROESTER, MASSACHUSETTS.

KNIFE FOR TURNING IRREGULAR FORMS.

SPECIFICATION forming part of Letters Patent No. 454,041, dated June 16,1891.

' Application filed November 26.1890- Serial No. 372,667. (No model.)

To all whom it may concern.-

Be it known that I, THOMAS W. GARDINER, a citizen of the United States,and a resident of Worcester, in the county of Worcester,

State of Massachusetts, have invented a new and useful Improvement inKnives for Turning Irregular Forms, of which the following is aspecification, accompanied by drawings, in which I have represented afinishing knife for a last-turning machine embodying my invention, andin which- Figure 1 is a diagrammatic figure, in which is represented therelation of the model-last, model-wheel, block to be turned, and thecutter-head of a last-turning machine. Fig. 2 is a side view of thecutter-head of a last-turning machine. Fig. 3 is an edge or face view ofthe same, and showing the relation of the block to a finishing-knife ofmy improved construction. Fig. 4is a side view of a finishing-knifeembodying my invention and shown in full size and detached from thecutterhead. Fig. 5 is an edge view of thesupporting-ring, showing therear edge; and Fig. 6 is a sectional view in line X X, Fig. 5.

Similar letters refer to similar parts in the different figures.

My invention relates to the knife ordinarily used in a machine forturning irregular forms and known as the finishing-knife or the knife bywhich the last out is made in. the form as it is turned from the block.

I have represented the cutter-head of a lastturning machine, whichconsists of a cylindrical block A, mounted upon a revolving arbor andcarrying a series of knives 1 2 3 at 5, by which the surplus stock ofthe block is reduced, the last out being taken by a finishing-knife 6,which must exactly correspond with the model-wheel B in its curvatureand in its radial distance from the center of the revolving arbor uponwhich the cutterhead is mounted, in order to give the last the samecontour as the model from which the last is turned. This finishing-knifeis made in a curved form, the curvature corresponding with the curvatureof the rim of the model-wheel, and the action of the finishingknife isillustrated in the diagrammatic figure shown in Fig. 1 of the drawings,in which the relations-of the parts concerned in the improvement made byme are shown in their relation to each other, the construction of amachine for turning irregular forms being so well understood that adetailed illustration of the entire machine is not deemed necessary.

'In turning a last or other irregular form a model of the shape to beproduced is hung upon a slowly-revolving arbor whose axisis coincidentwith the axis of the model. model is represented at a, Fig. 1. The blockto be turned is mounted in an arbor coincident with the axis of themodel and having a corresponding rotating motion. shown at h. The modela and block b are carried in aframe capable of a swinging motion, towhich force is applied to press the model against a wheel B, turningupon a fixed stud and having a rim (1, provided with a circular face torest against the model a, the frame inwhich the model and block arecarried having a swinging motion, owing to the irregularity of the modelas it is rotated in contact with the rim of the model-wheel B, therebycarrying the block 1) toward or away from the cutterhead A. Thefinishing-knife 6 is attached to the cutter-head by a bolt passingthrough the.

stem of the knife, and as the knife is worn away by repeated use itsposition is varied on the cutter-head to bring the cutting-edge of theknife the same radial distance from the axis of the cutter-head as therim of the wheel B. As the cutting is chiefly performed upon one side ofthe knife, as represented in Fig. 1, the continued wear with the processof sharpening theknife changes the cu rvature of the knife, so that itfails to shape the turned block in exact correspondence with the model.The preservation of the finishing-knife in a machine for turningirregular formsis, therefore, a diflicult task. To obviate thesedifficulties is the object of my invention, and I accomplish this objectby means of the knife and knife-holder shown in the accompanyingdrawings. In place of the ordinary form of finishing-knife (representedin Fig. 1 at 6) I attach to the cutter-head A, by means of a bolt f, inthe usual manner, the stem G, upon the outer end of which is a ring H,preferably formed integrally with the stem G. This ring is formed withan internal bearing H to re- Such a.

This block is ceive the annular knife 0, which is journaled in thebearing of the ring H, and is held in place by the spring-catches j j j,extending through the ring H and engaging the opposite edge. The body kof these spring-catches is made to clear the inner surface of the ring,so as not to impede the free rotation of the annular knife in itsbearing. The diameter of the annular knife at its cutting-edge D isexactly the same as the diameter of the rim of the model-wheel B incontact with the model a. As the cutting action of the knife as it isbrought into contact with the block to be turned is at one side of theplane of rotation of the center of the annular knife, the knife will bemade to rotate in its bearing by the resistance of the work against itsedge. The entire cutting-surface of the knife is thus brought intoaction, causing the wear to be uniform around its entire extent.

When dull the knife is readily removed from the ring H by thecompression of the spring-catches, and as the cutting-edge D is circularand continuous I am able to sharpen the knife by a circulargrinding-wheel working against the inside of the knife and grinding itequally upon all sides, thereby preserving the diameter and truecircular shape of the knife. When it becomes necessary to replace theknife, the ring-holder H need not be removed, but a new knife can beinserted in the holder and the radial position of the knife preserved.The constant adjustment of the knife to correct the variations caused bythe wear of the knife is therefore entirely avoided, and the duration ofthe knife is extended, as the cutting-edge is greatly increased.

I do not confine myself to the specific construction shown and describedwhereby the annular knife is held in its holder, as other means canobviously be employed for the purpose.

What I claim as my invention, and desire to secure by Letters Patent,is-

1. In a machine for turning irregular forms, the finishing-knifeconsisting of a ring or holder attached to a revolving cutter-head andan annular knife capable of being turned in said ring or holder, so asto bring different sections of its cutting-edge into action,substantially as described.

2. In a machine for turningirregular forms, the finishing-knifeconsisting of an annular ring having a continuous cutting-edge forming acomplete circle and carried bya revolving cutter-head, substantially asdescribed.

3. In a machine for turning irregular forms, the combination, with arevolving cutter-head, of an annular knife-holder carried by saidcutter-head and an annular knife journaled in said holder, so as to berotated by the contact of the knife with the worlgsiibstantially asdescribed.

4. In a machine for turning irregular forms, the combination, with arevolving cutter-head, of a knife-holder attached to said cutter-head,an annular knife held in and capable of being turned in said holder, andspring-catches attached to said annular knife and engaging saidknife-holder, substantially as described.

5. In a machine for turning irregular forms, the combination, with arevolving cutter-h cad, of an annular ring H, provided with a stem G, bywhich it is attached to said cutter-head, and an annular knife 0,journaled in said ring, substantially as described.

Dated at lVorcester, in the county of WVorcester and State ofMassachusetts, this 22d day of November, 1890.

Tl-IOS. W. GARDIN ER. Witnesses:

RUFUS B. FOWLER, H. W. FOWLER.

